The use of hydrogen peroxide as an oxidizing agent is generally well known. Hydrogen peroxide can be used, for example, for the oxidation of organic substances in solution, the synthesis of organic compounds, the oxidation of alcohols and aldehydes etc. In addition to bleaching, its use in the chemical industry and, more particularly, the field of environmental protection have become increasingly important. In the field of evironmental protection in particular, the great advantage of hydrogen peroxide makes itself felt, namely that pure water is produced as a decomposition product during the reaction of hydrogen peroxide. A main field of application for hydrogen peroxide therefore is also in effluent treatment (compare for example, H. Schwarzer, Chemie-Technik 8 (1979), 67-70 and 283-286; H. Overath NATO Techn. Bericht CCMS-111 (1979) 544).
It is also well known to activate hydrogen peroxide, with the formation of hydroxyl radicals (OH.sup.-) in order to increase the oxidation effect of hydrogen peroxide. The hydroxyl radical is one of the strongest chemical oxidizing agents.
A process which takes place with the formation of OH.sup.- is, for example, oxidation with Fenton's reagent, which is a mixture of hydrogen peroxide and iron(II) salts (compare, for example, H. J. H. Fenton, J. Chem. Soc. 65 (1984), 899-910; W. Feuerstein et al, Vom Wasser 56 (1981), 35-54). Oxidation with Fenton's reagent is therefore used also for effluent purification. Apart from the relatively high costs of Fenton's reagent, which become less important in the face of the urgency that frequently exists, for example during the decomposition of waste dump seepage, highly toxic, biologically non-degradable process effluent from the chemical industry etc, there remains, however, an important disadvantage regarding chemical activation of hydrogen peroxide because additional metal oxide/metal hydroxide slurries are produced as a result of the use of iron(II) ions. These slurries have to be disposed of in a sepcial way because, for example, there is the danger of redissolution by acid rain. The advantage associated with the use of hydrogen peroxide, namely that pure water is produced as a decomposition product during the reaction of hydrogen peroxide is, therefore, limited again to a large extent by the use of chemical activating agents. Therefore, the generally applicable use of chemically activated hydrogen peroxide for effluent purification did not achieve acceptance because of the disposal problem of the resulting metal hydroxide sludge.
In CH Pat. No. 605 421 discloses a process for the disinfection of bath-, drink- and industrial water using H.sub.2 O.sub.2 and catalytically active metals, metal ions or metal compounds, or organic substances e.g. aldehydes or a current source to effect a catalytic degradation of H.sub.2 O.sub.2. The catalysis by a current source is described using copper electrodes together with H.sub.2 O.sub.2 in amounts between 0 and 10 mg/l for disinfection of bacteria containing water. However under the conditions disclosed copper is dissolved, which results again in formation of undesirable metal oxide/metal hydroxide sludge.